Idmax went against the PG rsd in a review. This wasn't the Rsdc. The Rsdc is better then the regular rsd so I think its a pretty darn good sub.
This is what he said: "Well when you look at this sub verus the other you almost laugh I put it into the test, and I was thinking the same thing. Any how I powered it up, and I WAS SHOCKED, to simply put it. This woofer was amazing, it output was neck and neck with the IDMAX, it was very tight in the 50hz-80hz range, and hit low with authority. The sub is in the same league as the other and was better then most all-round actually."
50hz-80hz
Alumapro RX=10 (tight, extremely tight, and played every note)
IDMAX=8 (hit every note with uphm but not as tight pro and rsd)
RSd=8.5 (hit the notes very tight not as tight as the pro, but had a ti bit more uphm with the notes)
Flatline=4(Was not great, just your avg woofer)
w6v2=8(very similar response to IDMAX)
w3v2=4 (your avg woofer and to me little boomy)
p1=1.5 (p1 enough said)